util: qemu: Add support for user-passed strings in JSON->commandline

Until now the JSON->commandline convertor was used only for objects
created by qemu. To allow reusing it with disk formatter we'll need to
escape ',' as usual in qemu commandlines.

src/util/virqemu.c

@@ -46,7 +46,8 @@ virQEMUBuildCommandLineJSONRecurse(const char *key,
 
     switch ((virJSONType) value->type) {
     case VIR_JSON_TYPE_STRING:
-        virBufferAsprintf(buf, ",%s=%s", key, value->data.string);
+        virBufferAsprintf(buf, ",%s=", key);
+        virQEMUBuildBufferEscapeComma(buf, value->data.string);
         break;
 
     case VIR_JSON_TYPE_NUMBER:

tests/qemucommandutiltest.c

@@ -100,6 +100,7 @@ mymain(void)
 
     DO_TEST_COMMAND_OBJECT_FROM_JSON("{}", NULL);
     DO_TEST_COMMAND_OBJECT_FROM_JSON("{\"string\":\"qwer\"}", "string=qwer");
+    DO_TEST_COMMAND_OBJECT_FROM_JSON("{\"string\":\"qw,e,r\"}", "string=qw,,e,,r");
     DO_TEST_COMMAND_OBJECT_FROM_JSON("{\"number\":1234}", "number=1234");
     DO_TEST_COMMAND_OBJECT_FROM_JSON("{\"boolean\":true}", "boolean=yes");
     DO_TEST_COMMAND_OBJECT_FROM_JSON("{\"boolean\":false}", "boolean=no");